ADLINK PCI-7200 User Manual

Page 42

The following bits are used to check interrupt status:

SO_ACK: Status of O_ACK interrupt

1: O_ACK Interrupt occurred
0: No O_ACK interrupt

SI_REQ: Status of I_REQ interrupt

1: I_REQ Interrupt occurred
0: No I_REQ Interrupt

SI_T0: Status of timer 0 interrupt

1: OUT0 (output of timer 0) Interrupt occurred
0: No timer 0 Interrupt

SI_T1: Status of timer 1 interrupt

1: OUT1 (output of timer 1) Interrupt occurred
0: No timer 1 Interrupt

SI_T2: Status of timer 2 interrupt

1: OUT2 (output of timer 2) interrupt occurred
0: No timer 2 Interrupt

Note:

Writing “1” to the corresponding bit of the register can clear

all interrupt statuses. In order to make the interrupt work

properly, the interrupt service routine has to clear all the in-

terrupt status before end of the ISR.

Timer Configuration Control:

The 8254 timer on the PCI-7200 can be configured as either

timer 0 cascaded with timer 2 or timer 1 cascaded with timer

2. These configurations are controlled by the following bits:

T0_T2: Timer 0 is cascaded with timer 2

1: Timer 0 and timer 2 are cascaded together; output of timer

2 connects to the clock input of timer 0.
0: Not cascaded, the 4MHz clock is connected to the timer 0

clock input.

T1_T2: Timer 1 is cascaded with timer 2

1: Timer 1 and timer 2 are cascaded together; output of timer

2 connects to the clock input of timer 1.
0: Not cascaded, the 4MHz clock is connected to the timer 1